Consolidated Statement of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 872,981	$ 567,797	$ 674,035
Adjustments to reconcile net income to net cash provided by operating activities:
(Reversal of) provision for credit losses	(35,000)	210,653	98,685
Depreciation and amortization	156,792	119,908	144,178
Accretion of discount and amortization of premiums, net	33,467	(16,456)	(22,379)
Stock compensation costs	32,567	29,237	30,761
Deferred income tax benefit	4,762	(41,515)	(21,604)
Net gains on sales of loans	(8,909)	(4,501)	(4,035)
Gains on sales of AFS debt securities	(1,568)	(12,299)	(3,930)
Net gains on sales of other real estate owned ("OREO") and other foreclosed assets	(1,977)	(207)	(233)
Impairment on OREO and other foreclosed assets	5,151	3,717	9
Loans held-for-sale:
Originations and purchases	(11,155)	(81,662)	(10,569)
Proceeds from sales and paydowns/payoffs of loans originally classified as held-for-sale	12,552	80,659	10,436
Proceeds from distributions received from equity method investees	13,117	8,786	3,470
Net change in accrued interest receivable and other assets	124,496	(340,566)	(172,506)
Net change in accrued expenses and other liabilities	(29,412)	170,420	6,015
Other net operating activities	558	(1,327)	812
Total adjustments	295,441	124,847	59,110
Net cash provided by operating activities	1,168,422	692,644	733,145
Net (increase) decrease in:
Interest-bearing deposits with banks	73,263	(613,400)	170,455
Investments in qualified affordable housing partnerships, tax credit and other investments	(189,836)	(154,887)	(146,902)
Resale agreements:
Proceeds from paydowns and maturities	982,694	450,000	650,000
Purchases	(1,876,197)	(800,000)	(325,000)
AFS debt securities:
Proceeds from sales	308,812	525,433	627,110
Proceeds from repayments, maturities and redemptions	1,766,184	2,070,131	1,155,002
Purchases	(6,779,655)	(4,758,254)	(2,303,317)
Loans held-for-investment:
Proceeds from sales of loans originally classified as held-for-investment	606,410	331,864	288,823
Purchases	(1,045,456)	(389,863)	(524,142)
Other changes in loans held-for-investment, net	(2,877,438)	(3,546,596)	(2,183,665)
Premises and equipment:
Proceeds from sales	329	5,154	403
Purchases	(6,017)	(2,656)	(9,859)
Proceeds from sales of OREO and other foreclosed assets	54,338	295	1,224
Purchase of bank-owned life insurance	(150,000)	0	0
Distributions received from equity method investees	14,440	15,901	9,502
Other net investing activities	925	(6,858)	(2,560)
Net cash (used in) provided by investing activities	(9,117,204)	(6,873,736)	(2,592,926)
CASH FLOWS FROM FINANCING ACTIVITIES
Net increase in deposits	8,464,285	7,482,845	1,903,717
Net (decrease) increase in short-term borrowings	(21,143)	(9,016)	(28,535)
FHLB advances:
Proceeds	400	10,300	1,500,000
Repayments	(405,400)	(105,300)	(1,082,001)
Repurchase agreements:
Proceeds	0	48,063	0
Repayment	0	(198,063)	0
Extinguishment cost	0	(8,740)	0
Long-term debt and lease liabilities:
Proceeds from long-term debt	0	1,437,269	0
Repayments of long-term debt and lease liabilities	(1,206)	(1,438,335)	(884)
Common stock:
Proceeds from issuance pursuant to various stock compensation plans and agreements	2,573	2,326	3,383
Stocks tendered for payment of withholding taxes	(15,702)	(8,253)	(14,635)
Repurchase of common stocks pursuant to the Stock Repurchase Program	0	(145,966)	0
Cash dividends paid	(188,762)	(158,222)	(155,107)
Net cash provided by financing activities	7,835,045	6,908,908	2,125,938
Effect of exchange rate changes on cash and cash equivalents	8,701	29,006	(6,385)
NET (DECREASE) INCREASE IN CASH AND CASH EQUIVALENTS	(105,036)	756,822	259,772
CASH AND CASH EQUIVALENTS, BEGINNING OF YEAR	4,017,971	3,261,149	3,001,377
CASH AND CASH EQUIVALENTS, END OF YEAR	3,912,935	4,017,971	3,261,149
Cash paid during the year for:
Interest	87,684	233,139	418,840
Income taxes, net	139,460	116,416	158,296
Noncash investing and financing activities:
Loans transferred from held-for-investment to held-for-sale	599,610	329,069	285,637
Loans transferred to OREO	$ 49,485	$ 19,504	$ 2,013